Author Topic: Pellet alloy  (Read 246 times)

Alan

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Pellet alloy
« on: February 25, 2019, 04:28:57 AM »
Bullfrog's recent comment about shooting a deer with a .357 JSB pellet (it didn't appreciably flatten) leads (no pun) to ask this question. Is there a difference in alloy between say a .25 caliber JSB and a .357 JSB? From my experience, I believe there is.


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Alan

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cpt_sfc

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Re: Pellet alloy
« Reply #1 on: April 05, 2019, 07:01:10 AM »
A quick way to determine the hardness is to run your thumb nail hard across the nose of the pellet/bullet it will let you know the softness or hardness.

rsterne

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Re: Pellet alloy
« Reply #2 on: April 05, 2019, 07:50:45 AM »
I have a set of pencils, I will test them and tell you later today.... My fingernails are about BHN 11, so will scratch anything softer.... YFMV....

Bob
« Last Edit: April 05, 2019, 11:19:34 AM by rsterne »
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cpt_sfc

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Re: Pellet alloy
« Reply #3 on: April 05, 2019, 09:02:11 AM »
Years ago I used to shoot PPC and police match's Back in old days. I used to ck the 38 and 45 ammo and tried not to shoot the lead bullets that I could mark with my nail , it leaded up the barrels to bad so I cast my own and added type set metal to the mix Antimony  I think. You guys are way ahead of me with the science on this stuff.

rsterne

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Re: Pellet alloy
« Reply #4 on: April 05, 2019, 11:18:54 AM »
I just tested all the JSB Exact pellets I have in the larger calibers, using a scratch test with Staedler pencils, with the following results....

.25 cal King 25.4 gr.... 6B pencil will barely mark while crumbling, 5B will make a definite scratch mark....
.25 cal King Heavy 34.0 gr.... SAME AS ABOVE....
.30 cal 44.8 gr.... SAME AS ABOVE....
.35 cal 81.0 gr.... SAME AS ABOVE....

I have tested this set of Staedler pencils and my best estimate of hardness for the above results is BHN 6-7.... This is about what you would get with pure lead with about 1% tin.... I can state that all the above pellets are virtually the same hardness....

I did have one strange result, on JSB Exact pellets that are no longer available.... When JSB first produced .35 cal pellets, they weighed and were marked 77.6 gr.... and had a dark grey coating.... The surface could barely be marked with a fingernail, and they were obviously made from a harder alloy.... I still have some, and tested them with my pencils, both with the coating in place, and with the nose sanded flat to remove the coating, with the following results....

.35 cal 77.6 gr. with Coating.... 3B pencil will barely mark while crumbling, 2B will make a definite scratch mark.... BHN 10-11....
.35 cal 77.6 gr. without Coating.... 5B pencil will barely mark while crumbling, 4B will make a definite scratch mark.... BHN 8-9....

So, there are my results for hardness testing on JSB Exact pellets.... In previous testing of .177 and .22 cal I found them to be the same as the .25 cal.... so it would appear that JSB pellets are made from nearly pure lead, and are amongst the softest pellets available.... My NOE pellets cast from 40:1 alloy (2.5% tin) require a 5B to make a shallow scratch, I would estimate them at BHN 7-8.... Crosman pellets are harder, requiring a 4B pencil to make a shallow scratch, which would put them at about BHN 9....

As I said, my fingernails will scratch any alloy BHN 11 or softer, but will not scratch BHN 12.... so about all that tells you is if your fingernails are similar to mine, and they won't scratch the bullet or pellet, it's pretty hard for airgun use....  ::) …. YFMV (your fingernails may vary) of course....  ;)

Bob

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steveoh

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Re: Pellet alloy
« Reply #5 on: April 05, 2019, 01:02:42 PM »
With two .257 rifles that appear to be prone to leading, I am very interested in avoiding fouling if at all possible.

Here's a quote from a thread on the GTA:

Quote
Saw this quote from a thread on barrel fouling:

"That Fouling is from the antimony that is added to the lead, It makes the lead harder, Each manufacture uses it's own recipe % of antimony in their pellets.  This also helps Lessening the damage to the pellet skirts when shipping = Less complaints!!  It also allows keeping the pellets from deforming as much on impact increasing penetration. The {Fact} is the down side of the "antimony in pellets" is their tendency to foul bores quicker than pure lead pellets. Pure lead is infact a very good lubricant!"

Here's the thread: https://www.gatewaytoairguns.org/GTA/index.php?topic=134461.0

In the meantime I ordered some pure tin from RotoMetals. I've got it, but for some reason am holding off on using it. I suppose I want to see how clean barrels in the .257's behave with super clean bores that I've lubed, and will be shooting silicone lubed bullets through.  I don't want to spend 2 hours per rifle cleaning after a shooting session anymore. Nope.

Going through a critter or mushrooming isn't much of a concern since I mostly just shoot steel these days.

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d_boom

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Re: Pellet alloy
« Reply #6 on: April 12, 2019, 05:39:48 AM »
Hardness of pellets can be checked relative to pure lead by a simple check I have used to adjust a unknown
lead alloy's hardness when I cast bullets.  Two disks are needed, usually made by casting, one of pure lead
and the other from the pellets to be checked for hardness.  A ball bearing (.5") is pressed between two lead
disks using a vise.  The ball bearing only need to go partially into both disks, do NOT completely press the ball
bearing into the disks!  Accurately measure the diameters of impression in the disks.  By comparing the diameters
of the impressions will tell if the pellets are harder than lead. 
 

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Bullfrog

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Re: Pellet alloy
« Reply #7 on: April 22, 2019, 09:16:33 AM »
I still have that .357 JSB pellet somewhere. It has some scratches on the head and otherwise had no deformation. It was marketed as 81 grains in the tin. I have shot pellets from that same tin into wooden fence posts and those did show some deformation where they were smashed inside of the post.

To what degree does overall pellet size contribute to the structural integrity of a pellet? Could a .25 skirt or head deform where a .35 would not, where both pellets are made of the same lead alloy but the .35 is thicker at the points of deformation?

Alan

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Re: Pellet alloy
« Reply #8 on: April 22, 2019, 10:43:39 AM »
Almost any animal we nominally shoot with a "pellet" gun, is going to be a pass through. Finding the expended pellet isn't an easy task. And when you do find one, it is usually buried in something harder than the animal it went through. So the truth is, we don't know much about terminal ballistics in "animals", at least small ones.

The terminal ballistics caused by bullet-shooting airguns, act more like firearms of similar FPE. Although their terminal ballistics are better known, we still don't know what actual deformation occurs, for the same reason expressed above. This sort of brings up another issue.

We all see photo advertisements, depicting perfectly-mushroomed bullets, taken from large game. What you don't see (or read), is what the bullet hit causing it to mushroom. I'm lucky enough to have hunted a lot of big game others only dream about. Based on that experience, almost all of the game I've brought down, were killed with pass throughs. Those that remained within the animal were seldom mushroomed. Rather, they were deformed, and a few almost bent into two pieces. Those that were mushroomed, passed though more than one bone. Again, this points out the fact, that terminal ballistic data, taken from tissue approximations—clay, gelatin, etc.—are just that; approximations!
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Alan

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